Communication systems that include master node/remote node communication include the Synchronous Optical Network (SONET) and Asynchronous Transfer Mode (ATM) networks in which optical data signals are converted into electronic signals at each node of the network. The electronic signals are then decoded in order to make routing decisions before data is retransmitted optically down a selected path. Such optical-to-electronic-to-optical conversion at each network node requires expensive active equipment that generally must operate at the full network bandwidth.
One all-optical routing method that reduces the number of optical-electronic conversions is wavelength division multiplexing (WDM) in which different nodes of a network receive different optical signals having different center wavelengths. A communication hub sends data to a selected destination by selecting a suitable wavelength, either by switching between several lasers that emit at different center wavelengths, or by selectively tuning a single, tunable laser source. Unfortunately, telecommunication-grade tunable lasers are not readily available, and providing multiple lasers is expensive.
For these reasons, improved optical communication systems, networks, and methods are needed.